Polishing apparatus



April 12, i938 A. E. HAM-5N 2,113,836

POLISHING APPARATUS OriginaINFiled April @1955 INVENTOR Patented Apr.12, 1938 UNITED STATES POLISHING APPARATUS Alfred E. Hamilton,Pittsburgh, Pa.

Application April 6, 1935, Serial No. 15,067 Renewed December 8, 1936 3Claims.

My invention relates to polishing apparatus and .more particularly tothose of thetype customarily classified with bufling' wheels andgrinding wheels. The invention is particularly suitable for thepolishing of various articles such as knife blades, axes,metallicarticles generally, and particularly those having irregular curves andthicknesses.

Heretofore it has been common practice to employ polishing rolls-orwheels builtup of felt or other fabric, and having some yieldability,but suchpolishing rolls become hardened in time and have to befrequently renewed at great ex-- pense. Furthermore, they are notsufliciently yieldable to permit of uniform polishing of articles whichare not of uniform thickness, as for example, in the case of most knifeblades, axes, and the like.

One object of my invention is to provide a bufilng wheel or roll of suchform that it can be rendered sufllciently yieldable to avoid excessivepolishing or grinding on the thicker areas of articles which are ofnon-uniformthickness, and which on the other hand, willexert suflicientpolishing pressure against the thinner sections of the articles beingoperated upon.

Another object of my invention is to provide a polishing roll or wheelof such form that the degree of yieldability thereof can be readilychanged at the will of the operator.

Still another object of my invention is to provide a polishing andbufllng tool of such form that worn abrasive carrying elements can bequickly replaced at small expense.

35 Some of the forms which my invention may take are shown in theaccompanying drawing wherein Figure 1 is a longitudinal sectional viewthrough a. pair of polishing rolls; Fig. 2 is a view taken on the lineIII-11 of Fig. 1; Fig. 3

40 shows a modification of one of the polishing rolls of Fig. 1; Fig. 4shows still another modification;

Fig. 5 is an edge view of an abrasive-carrying sleeve for one of thepolishing wheels, andFig. 6

is a face view thereof.

Referring first to Figs. 1 and 2, I show roll stands 8 that support apair of polishing rolls 9. The rolls 9 are mounted on shafts In whichare driven from any suitable source of power, and at desired rates ofspeed.

The rolls 9 may be or identical construction, and therefore only one ofthem is shown in section. The body portions of the rolls mayconveniently be of yieldable material such as reinforced rubber orrubberized fabric, and are rigidly secured to the shafts III in anysuitable manner. As shown in the drawing, the rolls are composed mainlyof rubber, reinforced by fabric that is. imbedded therein, the hubportions 9a of the rolls being stretched onto the shaft, or may be heldthereon by pressureapplied interiorly of 5 the rolls.

An abrasive covering II is provided for each roll, which cover may be inthe form of a sleeve 'made of walrus skin, canvas or other fabric,

or of any flexible material to which an abrasive 10 such as emery may beapplied. The sleeves can be placed on the rolls by contracting the rollsslightly, and then permitting them to expand.

The rolls have'intemal annular ribs 12 formed integrally therewith, andof increasing thickness 15 toward the middle of the rolls at which pointthere is, of course, greater tendency toward radial displacement, eitherthrough centrifugal forces or through pressure applied against theperiphery of the rolls. A valve I3 is provided in an end of each of therolls through which valve air under pressure may be introduced. Thedegree of pressure provided within the rolls 9 will be dependent, ofcourse, upon the extent to which it is desired that the rolls shallresist pressuresagainst their peripheries.

It will be understood that the articles to be polished are moved intothe roll pass and then withdrawn, or passed'entirely through the rolls,depending upon the nature of the articles being ground and polished. Inthe case of knife blades, for example, wherein the thickness may varygreatly, the pressure within the rolls 9 may be maintained fairly high,especially if considerable polishing pressure is desired. 0n the otherhand, where the article operated upon varies greatly in thickness, theair pressures within the "rolls will'be reduced somewhat so there willnot be excessive polishing pressures on the thicker portions of thearticles, and so that the thinner 40 portions of the articles will beadequately engaged by the rolls.

The ribs I! serve not only to stiifen the rolls somewhat against inwarddeflection, especially when air pressures within the rolls are low, but

they resist excessive displacement under centrii ugal forces when therolls are rotated rapidly.

For some classes of work, the air within 'the rolls' may be atatmospheric pressures, and there may be' cases where it'is desirable tocreate subatmospheric pressures-within the rolls, in which instances,the rolls can be rotated so rapidly that they will distort radiallyunder centrifugal force, and therefore exert a lighter polishingpressure than where there is super-atmospheric pressure within therolls. In either event, however, the polishing pressure within certainlimits can be controlled by regulating the speed of rotation of therolls.

Referring now to Fig. 3, I show a polishing wheel l4 which may be ofreinforced rubber, and which is provided with an internalcircumferentiallyextending rib l5 which yieldably resists radialdisplacement of the peripheral wall of the wheel, as in the case of theribs II. In this instance, an

abrasive-carrying sleeve 16 can he slipped into place on the wheel,whenever desired, and a valve I I is provided for the introduction of adesired quantity of air to-the interior of the wheel to render the samemore or less yieldable, as may be desired. The periphery of the wheel I4is concave in directions axially of the wheel, to accommodate articleswhose surfaces are curved. The rolls of Fig. 1, of course, are capableof properly polishing curved articles which are not too sharply curved,but the wheel of Fig. 4 will more accurately polish articles curved onextremely short and varying radii.

In Fig. 4, I show a polishing wheel l8 that is of the same general formas the wheel H, but which has two annular ribs IS in its side walls,instead of a peripheral stifiening rib. The ribs l9 will permit ofgreater radial movement or depression of the peripheral wall of thewheel at its central line,

but will resist displacement of the side walls of the wheel.

The wheels l4 and I8 as in the case of the rolls 9 at their ends orperipheral corners, are of greater diameter than at points intermediatetheir ends,

tions will prevent the sleeves from shifting axially on the wheels whenin use.

The wheels of Figs. 3 and 4 can be used singly,-

and can also be mo nted in side-by-side groupings upon shafts suc as theshafts l0.

It will be understood that the polishing rolls and wheels are capable ofbeing used for general grinding, bufling, and polishing operations, andwith various kinds of grinding and polishing materials. Also, thatabrasive material could be directly imbedded in the peripheral surfacesof the rolls or wheels, and that the polishing tools need notnecessarily be in the form of wheels or rolls.

The terms wheels, "rolls and drums are employed in a broad sense, sinceit is obvious that a roll is in efiect a wheel that is of relativelygreat dimension in an axial direction.

I claim as my invention:-

1. A polishing device of drum-like form closed at its ends, and providedwith. annular ribs axially spacedon its inner peripheral wall, all ofsaid elements being of yieldable material.

2. A polishing device of drum-like form closed at its ends, and providedwith annular ribs on its inner peripheral wall, all of said elementsbeing of yieldable material, and those ribs near the mid portion of thedrum being of greater thickness than the other ribs.

3. A polishing device of drum-like form closed at its ends, and providedwith annular ribs axially spaced on its inner peripheral wall, all ofsaid elements being of yieldable material, and means for maintaining airat a desired pressure within the device.

ALFRED E. HAMILTON.

